Apparently there was a recall for an ECU reflash for the 2010's for the exact same problem you are having.
The 2011's seem to have the same problem and quite a few 2011 owners had there ECU reflashed with great results.
Its a low rpm rich condition problem.
The 500's Engine are super finicky.
They're tuned from the factory to pretty much be hung wide open all the time.
Don't run anything over 87 octane !!!
Sounds crazy but ask any Arctic Cat dealer or racer that knows the 500's.
I have got wife's sled reflashed two times and no difference.Most likely the ECU is just in need of a reflash.
It was a recall available to correct sleds that were effected by the bog you are describing.
It most commonly effected and generally occurred on sleds that were just "gunned" from idle, creating a rich bog.
On mine, it most commonly occurred when the engine was cold and I learned to increased RPM's less abruptly and it reduced the likelihood of the bog.
I have worked on MANY of the 500's and worked one on one with quite a few racers.
I have lost count of the amount of hours spent on the dyno and on the phone with Arctic Cat and spoke to their "EFI specialist" several times.
I get a lot of feedback from people out on the trail and that come in for service and the response seems to be a trend.
We are talking box stock 500's.
I can assure you that Arctic Cat will tell you to run 87 Octane.
That's coming from their "EFI specialist"
We did some of the updates on the 2010's and used that same ECU map on some of the 2011's.
Arctic Cat didn't do the best job with the low rpm fuel curve.
We have two 500's in the shop now.
A couple things come to mind. Air temp sensor is one of them.
Was this "incident" after riding, then stopping for a bit, and then starting off again ?
We had some "want to die" issue, they would start up fine, but when you went to drive away, the sled would die right off.
This was after riding, then stopping and then heading off again.
We ended up relocating the air sensor and that seemed to correct the problem.
Seemed that when we stopped, the air in the air box would warm up while sitting from under hood temps.
When we started up again, the ECU would recognize the warm air, lean the sled out for THAT temp, but when we'd push the throttle, cold air would then enter the motor... and voila ... lean condition.
Once and for all: This is a 500 cc non APV engine problem, not connected to a certain chassi or year !I was just searching for that exact same problem.
I have a ( 2012 ) Sno-Pro 500 with D+D porting/head mod.
On warm days and a couple times after stopping then restarting to move the sled, it would bog and almost die unless you feathered the throttle a lot.
I also was thinking that the problem is the air temp sensor because once the airflow came back Engine ran perfect.
I have a 2011 that wants to die right after I get gas and going slow through the parking lot but I let off the throttle and it comes back and never had to restart it. Now I'm leaking coolant probably from water pump, any threads on that here yet?I have never owned the sno pro 500 i'll give you that one but I have worked on MANY of them and worked one on one with quite a few racers. I have lost count of the amount of hours spent on the dyno and on the phone with arctic cat and spoke to their "EFI specialist" several times. The "not making great trail sleds" I honestly can't answer that personally I'll give you that one to. I get a lot of feedback from people out on the trail and that come in for service and the response seems to be a trend (not everyone). We are talking box stock sno pros. I can assure you that arctic cat will tell you to run 87. That's coming from their "EFI specialist" I gave my 2 cents. Seems like I struck a nerve. I'll retire from this thread.